Partial matching in the Moses illusion: response bias not sensitivity.

Previous research has demonstrated that people have enormous difficulty in detecting distortions in such questions as, "How many animals of each kind did Moses take in the Ark?" Reder and Kusbit (1991) argued that the locus of the effect must be the existence of a partial-match process. Other research has suggested that this partial-match process operates at the word level and that, with adequate focus on the relevant word, the Moses illusion is greatly diminished. The present experimental results argue that those conclusions were based on a shift in response criterion with no concomitant change in ability to detect distortions. Furthermore, the data suggest that the matching process operates below the word level, at the level of distinctive features.